A variety of coated articles can be fabricated by vacuum lamination for a variety of applications such as electronics, building, vehicle, healthcare, and consumer applications. For illustration, some electronics applications use coated electronic devices such as coated light emitting diodes. Light emitting diode (LED) devices including an array of light emitting diodes (LEDs) coupled to a substrate can be fabricated to generate light in different colors. One way for producing light of different colors or for otherwise controlling or manipulating the light generated from the LEDs is to deposit a phosphor material over the array of LEDs. There are many ways to do this. One of the most common ways is to dispense a mixture of phosphor and encapsulant over the LEDs. Another way is to mix phosphor particles in an uncured thermosetting binder material to form a preformed lamination layer, and then laminate this layer over the array of LEDs to form a conformal coating thereon. The lamination method commonly used is a vacuum lamination technique that includes two distinct heating steps, hereinafter referred to as a two-step vacuum lamination technique or method.
In this two-step vacuum lamination technique, the preformed lamination layer is first heated to temperatures high enough to achieve flow in the uncured thermosetting binder material, followed by a second heating step wherein the preformed lamination layer is reheated and conformally coated to the LED array. In this first heating step, the preformed laminated layer begins to cure (i.e., crosslink), therein reducing the flow characteristics of the layer, and hence the layer may be too stiff to be subsequently conformed during the second final heating step or, alternatively may be conformed but with substantial defects associated therewith. Still further, even wherein the curing conditions during these two-step vacuum lamination techniques are precisely controlled, the processing time encompassing the second heating step and subsequent conforming of the preformed lamination layer over the array of LEDs is limited due to the partial curing of the binder material in the first heating step. Also, the limited processing time during the second heating step and subsequent conformation step does not allow the two-step vacuum lamination technique to be used on arrays of LEDs of varying heights, and also limits the choices for binder materials and phosphor materials that may be used in two-step vacuum lamination techniques based upon this limited processing time.
Manufacturing other coated articles for a variety of applications such as other electronics applications, building, vehicle, healthcare, and consumer applications have many of the aforementioned lamination problems.
The present invention addresses many of the problems with lamination techniques utilizing two-step vacuum lamination technique described above.